Which classification system is used to determine the stage of tumors in cancer registries?

The TNM staging system is widely utilized in cancer registries to categorize the extent and severity of different types of tumors. This classification system provides a standardized method for describing the anatomical extent of cancer, allowing for effective communication among healthcare providers and aiding in the treatment planning and prognosis.

In the TNM system, "T" refers to the size and extent of the primary tumor, "N" indicates the absence or presence of regional lymph node involvement, and "M" describes whether there is distant metastasis. This detailed categorization is crucial in determining the overall stage of cancer, influencing treatment options and outcome predictions.

While other systems, such as FIGO and AJCC, also play important roles in cancer staging—FIGO primarily for gynecological cancers and AJCC often incorporating aspects of the TNM system—they do not match the broad applicability and specificity of the TNM system across various types of cancers. Breslow depth, which measures the thickness of melanoma tumors, is specific to melanoma staging and not used for a wide variety of cancers. Therefore, the TNM staging system is especially relevant for cancer registries given its comprehensive and systematic approach to staging tumors.